fix(watcher): auto-polling sur mounts reseau (NFS/SMB) pour maj temps reel des recents

inotify ne voit pas les ecritures faites depuis d'autres clients NFS
(Obsidian sur Windows), donc index_updated n'etait jamais emis et la
section Recent du sidebar ne se rafraichissait pas. Detection du fstype
par vault via /proc/mounts -> PollingObserver (stat-based) sur mounts
reseau, Observer natif conserve sur les mounts locaux.

tests/test_watcher.py

@@ -74,6 +74,80 @@ class TestIsRelevant:
         assert handler._is_relevant("/vault/Makefile") is True
 
 
+# ═══════════════════════════════════════════════════════════════════
+# Network-mount detection (NFS/SMB → polling watcher required)
+# ═══════════════════════════════════════════════════════════════════
+
+class TestNetworkMountDetection:
+    MOUNTS = [
+        "overlay / overlay rw 0 0",
+        "server:/export/NFS/OBSIDIAN_DOC /vaults/Obsidian_IT nfs4 rw 0 0",
+        "server:/export/home/bruno /vaults/bruno nfs4 rw 0 0",
+        "dev/sda1 /data ext4 rw 0 0",
+        "srv:/share /mnt/smb cifs rw 0 0",
+    ]
+
+    def test_nfs_mount_detected(self):
+        from backend.watcher import find_mount_fstype
+        ft = find_mount_fstype("/vaults/Obsidian_IT/note.md", self.MOUNTS)
+        assert ft == "nfs4"
+
+    def test_nested_nfs_mount(self):
+        from backend.watcher import find_mount_fstype
+        ft = find_mount_fstype("/vaults/bruno/sub/dir", self.MOUNTS)
+        assert ft == "nfs4"
+
+    def test_smb_mount_detected(self):
+        from backend.watcher import find_mount_fstype
+        ft = find_mount_fstype("/mnt/smb/file.md", self.MOUNTS)
+        assert ft == "cifs"
+
+    def test_local_fs_not_network(self):
+        from backend.watcher import find_mount_fstype
+        ft = find_mount_fstype("/data/file.md", self.MOUNTS)
+        assert ft == "ext4"
+
+    def test_unmatched_path_returns_empty(self):
+        from backend.watcher import find_mount_fstype
+        assert find_mount_fstype("/nowhere/file.md", self.MOUNTS) == ""
+
+    def test_longest_prefix_wins(self):
+        from backend.watcher import find_mount_fstype
+        lines = self.MOUNTS + ["tmpfs /vaults/Obsidian_IT/tmp tmpfs rw 0 0"]
+        assert find_mount_fstype("/vaults/Obsidian_IT/tmp/x", lines) == "tmpfs"
+        assert find_mount_fstype("/vaults/Obsidian_IT/other", lines) == "nfs4"
+
+    def test_escaped_space_in_mount_point(self):
+        from backend.watcher import find_mount_fstype
+        lines = ["srv:/x /vaults/My\\040Vault nfs rw 0 0"]
+        assert find_mount_fstype("/vaults/My Vault/a.md", lines) == "nfs"
+
+    def test_is_network_mount_false_on_windows(self, monkeypatch):
+        import backend.watcher as w
+        monkeypatch.setattr(w.os, "name", "nt")
+        assert w.is_network_mount("/vaults/x") is False
+
+    def test_watch_vault_uses_polling_for_network_mount(self, monkeypatch):
+        """_watch_vault must pick PollingObserver when is_network_mount is True."""
+        import asyncio
+        from unittest.mock import MagicMock
+        import backend.watcher as w
+
+        watcher = w.VaultWatcher(on_file_change=MagicMock())
+        monkeypatch.setattr(w, "is_network_mount", lambda p: True)
+        mock_poll = MagicMock()
+        monkeypatch.setattr(w, "PollingObserver", mock_poll)
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+            loop.run_until_complete(
+                watcher._watch_vault("NetVault", tmpdir, loop)
+            )
+            mock_poll.assert_called_once()
+            assert "NetVault" in watcher.observers
+
+
 # ═══════════════════════════════════════════════════════════════════
 # VaultWatcher (unit tests with mocks)
 # ═══════════════════════════════════════════════════════════════════